Diaminedioximes are a known class of chelating agents, which have been shown to form
                Q=—(CH2)3— ie. propyleneamine oxime or PnAO;        Q=—(CH2)4— ie. butyleneamine oxime or BnAO;        Q=—(CH2)5— ie. pentyleneamine oxime or PentAO;complexes with the radiometal 99mTc.        
The ligand PentAO was first disclosed by S. Jurisson et al [Inorg. Chem., 26, 3576-82 (1987], who showed that its' metal complex with the long-lived radiometal 99Tc was neutral, with a Tc(V) dioxo core (ie. TcO2+). J-M Lo et al [Appl. Rad. Inst, 44, 1139-46 (1993)] described the synthesis of PentAO and it's complexation with 99mTc.
U.S. Pat. No. 5,688,487 discloses chelate-conjugates of diaminedioximes having a C2-5 alkylene bridge with nitroimidazole biological targeting molecules, for hypoxia imaging. Conjugation of the nitroimidazole at the C1 (oxime methyl) position is described.
WO 95/04552 discloses nitroimidazole conjugates of BnAO and PentAO. The Example shows conjugation at the C1 (oxime methyl) position.
WO 95/19187 discloses conjugates of linear or cyclic 3-50 mer synthetic peptides with polydentate chelating agents attached at the peptide carboxyl terminus, for use as radiopharmaceuticals. Diaminedioximes such as PnAO, BnAO and PentAO are described as suitable chelating agents.
WO 99/60018 discloses diaminedioxime chelate conjugates of diaminedioxime ligands with peptides for thrombus imaging. A preferred such chelator is said to be a diaminedioxime with Q=—(CH2)2NR(CH2)2—.